/*
 * (C) Copyright 2006-2010 Nuxeo SAS (http://nuxeo.com/) and contributors.
 *
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the GNU Lesser General Public License
 * (LGPL) version 2.1 which accompanies this distribution, and is available at
 * http://www.gnu.org/licenses/lgpl.html
 *
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
 * Lesser General Public License for more details.
 *
 * Contributors:
 *     bstefanescu
 */
package org.nuxeo.gwt.habyt.invocation.server;

import javax.servlet.ServletConfig;

import org.nuxeo.gwt.habyt.invocation.client.Invocation;
import org.nuxeo.gwt.habyt.invocation.client.InvocationException;
import org.nuxeo.gwt.habyt.invocation.client.InvocationResponse;
import org.nuxeo.gwt.habyt.invocation.client.InvocationService;

import com.google.gwt.user.server.rpc.RemoteServiceServlet;

/**
 * @author <a href="mailto:bs@nuxeo.com">Bogdan Stefanescu</a>
 * 
 */
public class InvokerServlet extends RemoteServiceServlet implements
        InvocationService {

    private static final long serialVersionUID = 1L;

    protected volatile transient ServerInvoker invoker;

    public final ServerInvoker getInvoker() throws InvocationException {
        ServerInvoker _invoker = invoker;
        if (_invoker == null) {
            synchronized (this) {
                _invoker = invoker;
                if (_invoker == null) {
                    invoker = createServerInvoker(getServletConfig());
                    _invoker = invoker;
                }
            }
        }
        return _invoker;
    }

    protected ServerInvoker createServerInvoker(ServletConfig config)
            throws InvocationException {
        return new ServerInvoker(config);
    }

    @Override
    public InvocationResponse invoke(Invocation invocation)
            throws InvocationException {
        return getInvoker().invoke(getThreadLocalRequest(), invocation);
    }

}
